Main Menu

Green Space and Agriculture

Food security and sustainability in cities

Premise

In aggregate, the world produces enough food to feed the population of the Earth (FAO, 2011), with more people suffering from obesity-related malnutrition rather than food scarcity (The Lancet, 2013). Geographic discrepancies in food availability shows substantial differences between developing and developed nations and peoples’ access to food due to income, environmental pressure or efficacy of food delivery infrastructure.

Challenges

Population growth

The world’s population boom has been met with an increasing global urban population. This transition to over half of humanity residing within urban areas poses new challenges as people become further removed from the food sources and become part of increasingly abstracted food delivery systems. As well as this, it has been shown that as people move to urban areas, an increase in income and access to a wider variety of food varieties changes food consumption behaviour. In essence, the globally-available “Western Diet” that pervades results in exposure to nutrient-dense, but also resource-intensive foods that are high in saturated fats, sugars and processed ingredients.

A disconnect between urban populations and external food sources, potentially with transoceanic supply chains will produce an increasing risk of food crises, if supply if interrupted. The increasing global demand for global brands and a resource-intensive “Western diet” may put unsustainable pressure on agriculture, especially water and land use for pastoral farming and unmanaged fish stocks.

Climate

Hurricane Sandy, New York state, 2012 was a reminder of how delicate food distribution systems, even in developed nations, can be when faced with extreme events. Limited inventory and capacity in local supermarkets led to depletion of food supplies in the area due to initial panic buying. The power outages caused by the storm resulted in a breakdown of adequate and sanitary food storage resulted in a further loss of food stocks and any remaining supplies in warehoused units. Road closures prevented any replenishment of stocks by road for several days, triggering a panic.

Although the issue resolved itself quickly following road repairs or food delivery by other means, authorities were underprepared for the onset of a rapid food crisis and the breakdown of law and order. The looting and societal breakdown over a Sandy-like storm event poses serious questions as to the capability of current food distribution systems under stress. Furthermore, it underlined that lessons from the much more catastrophic hurricane Katrina, 7 years earlier, had yet to be learned and cities such as New York were just as vulnerable as New Orleans.

The frequency of these events, and their intensity, is projected to increase a result of increasing global temperatures. The question of how sustainable market-driven food supply networks are during ‘exceptional’ conditions remains unresolved. Future planning as to making cities more resilient and less dependent of external supply, at least for short term emergencies, must be considered.

The long term effects of climate change put pressure on the supply and availability of external food sources also. The recent ‘Millenium Drought’ in Australia showed how devastating a fluctuating climate can be on food production. Furthermore, changing climate is also attributed to the reduction of available land for agriculture, in addition to loss of land due to urban growth, but also depletion due to agricultural mismanagement.

Solutions

Application of the green belt – e.g. “Food Bowls” in Australia

Urban farming initiatives

Urban Farm, Chicago

Green Space in cities:

Provides a vital space for inhabitants, which facilitates exercise, play and well being, as well as increasing community cohesion.

Acts as an important buffer to environmental pressures.

Has the potential to increase biodiversity and act as an important ecosystem.

Source: World Cities Culture Report 2014

As can be seen in the graph above, the amount of green space varies in cities around the world, from over 50% in Moscow to less than 2% in Istanbul.

Innovation: Living Roofs

Living roofs are a way to increase the surface area of vegetation in a densely populated city. These roofs act as insulation, decreasing the cost of heating buildings, as well as increasing air quality by decreasing CO2 levels. They are also important for reducing the amount of impermeable surface area, which allows water to be taken up rather than running off and increasing the risk of flooding.

Increasing The Quality of Green Space

Although an increasing amount of green space sounds like a positive, the quality of the space is extremely important. Spaces that are isolated and not well maintained can become dangerous places that encourage anti-social behavior rather than community cohesion.

There is also a tendency to over maintain parks, with closely mowed grass and carefully planted boarders. Whilst this may look attractive, it discourages wildlife and decreases biodiversity. Setting aside areas such as wildflower meadows for pollinators can help to increase the diversity of these animals in the urban environment.

The London Outlook

London fares quite well on the amount of green space, in regards to other cities. There are a large number of public parks that are always busy with families and friends.

However, around 3.2M metres squared of roof space has the potential to be greened, out of a total 10M metres squared.

What can you do?

Public space is obviously important, however many cities also contain a large proportion of domestic gardens. Around 24% of Greater London domestic garden land, but only 14% of this is estimated to be green space. Increasing private green space would impact on the